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Math Help - Trying to help my brother.

  1. #1
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    Trying to help my brother.

    I am a seasoned mech eng and for whatever reason this problem is kicking my butt. Here goes.

    Find the smallest integer X so that 252*X is a perfect cube.

    Ok so you say y^3=252*X and thats as far as I got. Cant take derivatives since this is just trig, so Im stumped. Please help.
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  2. #2
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    I read the question improperly - my bad. :P
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  3. #3
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    Quote Originally Posted by lewisb13 View Post
    I am a seasoned mech eng and for whatever reason this problem is kicking my butt. Here goes.

    Find the smallest integer X so that 252*X is a perfect cube.

    Ok so you say y^3=252*X and thats as far as I got. Cant take derivatives since this is just trig, so Im stumped. Please help.
    252=2^2 3^2 7

    For x \times 252 to be a perfect cube every prime factor in its prime decomposition must appear with power 3. So x=2 \times 3 \times 7^2 is the smallest positive integer x that makes x \times 252 a perfect cube.

    CB
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  4. #4
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    Man thank you so much. That seems like some pretty advanced stuff to me. Geez.
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  5. #5
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